Electrical stimulation and drug delivery to portions of the anatomy, particularly the spinal anatomy and peripheral nervous system, often involve the implantation of one or more leads or delivery devices within the patient's body. The leads or delivery devices extend between the target anatomy and an implantable pulse generator (IPG) or drug reservoir which is typically implanted at a remote location. Precise positioning of the leads or delivery devices is desired to optimize treatment. Accuracy in administration of the drugs or stimulation to a particular target location can maximize beneficial effects of treatment and patient satisfaction. It is desired that such accuracy be maintained over time to ensure continued successful treatment.
For example, when implanting an epidural lead, a physician must surgically open the body tissue to the epidural space, and then insert the lead into the epidural space to the desired location. Fluoroscopy aids the physician, and trial and error tests of treatment define the desired location(s) for treatment. Once desirably positioned, it is desired to maintain the lead in place. Typically this is attempted by suturing the lead in place, such as by attaching a sleeve or anchor to the lead and suturing the anchor to the lead and to the surrounding tissue where the lead enters the epidural space. A variety of conventional anchors are available for such use. Some conventional anchors are comprised of silicone and are attached to the lead with sutures. However, such anchors often do not sufficiently grip the lead and the lead grip force is highly dependent on the suturing technique of the physician. Such suturing is time consuming, tedious and subject to error or variability. Further, any repositioning of the anchor along the lead requires removal of the sutures and resuturing. Other conventional anchors are attached to the lead with a mechanically actuated mechanism. Although such anchors are sometimes more effective in gripping the lead, the anchors can potentially damage the lead or cause severe deformation of the lead body. In addition, the mechanically actuated anchors are most suited for leads with relatively rigid bodies and are not suitable for leads having more flexible bodies.
It is desired to provide mechanisms for anchoring leads, catheters or other devices within body tissue that are easy and efficient to use, reliable, and adjustable. At least some of these objectives will be met by the present invention.